Is it our ghost?

[MarshallPope]

We were in the middle of our production of Bye Bye Birdie tonight, and we had an occurrence that neither I nor our TD nor our tech professor can find an explanation for. Out of curiosity, I am asking here.

I am sitting in my ASM post, and the grand is in in front of me and traveled open. It both flies and travels during the show, and we do not have a chance to attach the tension block to the floor. It had been open for probably around five minutes. Al of a sudden, I see, over the top of my music stand, the tension block steadily rising a good foot or so in maybe 1.5 seconds. I wait a minute and stare at it with the cast members who are standing next to me, then I walk over to it. Gently tugging on the hand line, it returns to its position.

Any idea why this would happen? Is there really enough give in the cotton hand line for it to stretch that much? Would a stretched line restore itself that quickly and suddenly after sitting still for that long? Is there something else in the mechanics of a traveler that could cause the block to rise? I'm at a loss trying to explain it.

 

[chausman]

If someone had bumped the curtain itself, and leaned hard enough, it could have pulled the tension block up. Thats the only thing I can think of.

 

[derekleffew]

MarshallPope, I bet the traveler is significantly wider than it is tall? Without the tension block attached to the floor or weighted, the return portion (part that does not go through the carriers) of the operating line will sag, lifting the block. I searched, but could not find a good illustration of this.

Who knows why it waited five minutes to sag, and thus raise the floor block, rather than as soon as the curtain was opened. Gravity storm?

 

[SteveB]

MarshallPope, I bet the traveler is significantly wider than it is tall? Without the tension block attached to the floor or weighted, the return portion (part that does not go through the carriers) of the operating line will sag, lifting the block. I searched, but could not find a good illustration of this.

Who knows why it waited five minutes to sag, and thus raise the floor block, rather than as soon as the curtain was opened. Gravity storm?

Ditto Derek's explanation. This happens all the time on our travelers, which are 48ft x 21ft or so

 

[Van]

Yep, No Ghosts, just gravity.

 

[MarshallPope]

That makes sense. I figured that there was -something- in there that could move, but I couldn't for the life of me think of what it might be. I wouldn't have expected that much weight to be in the operating line.

 

[Van]

It's nor even about the amount of weight it's about the difference between the weights. Remember that a balance scale works even if it's only 1 gram diffrence. give a nudge by bumping the curtain and you've added linetic energy to the sum total and Viola'.